Tag: Middle fossa

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Endoscopic Endonasal Transrotundum Middle Fossa Exposure: Technique of Transpterygoid Maxillary Nerve Transposition

World Neurosurg. (2018) 112:131-137

Middle fossa floor access can be challenging. Open skull base approaches have associated morbidity and yield suboptimal working angles around the temporal lobe. Endoscopic endonasal approaches to the middle fossa are poorly described, but provide an improved angle. I hypothesized that the length of the maxillary nerve can be transposed out of the foramen rotundum to provide a path to expose the full width of the middle fossa floor through the anterolateral and anteromedial triangle.

METHODS: Endoscopic endonasal transpterygoid dissections to expose the middle fossa were performed bilaterally on 2 silicone-injected cadaveric heads (4 sides). Transposition of V2 was then performed on all sides, and additional middle fossa exposure was achieved. Highresolution computed tomography imaging was obtained to quantify the extent of exposure. A transzygomatic approach was also performed for comparison.

RESULTS: The maxillary nerve was successfully transposed in each dissection. A periosteal fold was identified to assist in the mobilization of the infraorbital nerve. The average middle fossa exposure achieved without transposition was 50% (of the medial to lateral width). Transposition increased that to 95%. Comparison with the open transzygomatic approach demonstrated superior surgical trajectory (inferior to superior) with the endonasal route.

CONCLUSIONS: Endoscopic endonasal transpterygoid approaches with or without transposition of the maxillary nerve provide a reasonable option for sequentially exposing the entire medial to lateral extent of the anterolateral triangle. It provides an advantageous inferior to superior surgical angle and can be considered for treatment of select middle fossa floor pathology

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Endoscopic treatment of middle fossa arachnoid cysts

Acta Neurochir (2017) 159:2313–2317

Endoscopic treatment of middle fossa arachnoid cysts is an alternative option to microsurgical fenestration and shunting procedures. The procedure is minimally invasive and obviates the morbidity of craniotomy and shunting.

Methods Operative charts and videos of patients undergoing endoscopic fenestration of middle fossa arachnoid cysts were retrieved from the senior author’s database of endoscopic procedures and reviewed. Description of the surgical techniques was then formulated.

Conclusions Endoscopic fenestration of middle fossa arachnoid cysts entails communicating the cyst cavity to the basal cisterns via multiple fenestrations that should be made as large as possible with care to avoid injury of the juxtaposed neurovascular structures.

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Lateral Orbitotomy Approach for Lesions Involving the Middle Fossa

Neurosurgery 80:309–322, 2017

Classically used for treatment of orbital lesions,the lateral orbitotomy with cantholysis can be combined with a temporal craniectomy for lesions involving the middle cranial fossa.

OBJECTIVE: To present a single-center experience with the lateral orbitotomy approach for lesions involving the middle fossa.

METHODS: Twenty-five patients underwent lateral orbitotomies from April 2012 to July 2015. Excluding patients with solely intraorbital pathologies, 13 patients’clinical and radio- graphic records were retrospectively reviewed.

RESULTS: Signs/symptoms in the 13 patients (ages 28-81) included proptosis (69%), decreased visual acuity (31%), diplopia (54%), and afferent pupillary defect (69%). Pathologies were meningioma (8), esthesioneuroblastoma, lymphoma, chordoma, Ewing’s sarcoma, and squamous cell carcinoma. Surgical goals were maximal safe resection in 8 patients, palliative debulking in 3 patients, and cavernous sinus biopsy in 2 patients. In 8 patients for whom maximal resection was the goal, 2 had gross total resection, while 6 had near-total resection. All patients (3) for whom palliation was the goal had symptomatic improvement. Both cavernous sinus biopsies obtained diagnostic tissue without complications. All patients with proptosis (n = 9) and diplopia (n = 7), and 2 of 4 patients with decreased visual acuity had improvement in their symptoms. No patient reported worsening of their symptoms. Mean follow-up was 12 mo (2-30 mo). Complica- tions included oculorrhea (1), pseudomeningocele (2), transient ptosis (2), and forehead numbness (1).

CONCLUSION: The lateral orbitotomy is a promising approach for carefully selected lesions with involvement of both the lateral orbit and middle cranial fossa. It provides minimally invasive access for biopsy, decompression, or resection.

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Repair of middle fossa cerebrospinal fluid leaks using a novel combination of materials

Neurosurg Focus 32 (6):E8, 2012. (http://thejns.org/doi/abs/10.3171/2012.4.FOCUS1258)

Methods for repairing middle fossa CSF (MFCSF) leaks have varied and yielded mixed results. The objective of this study was to evaluate the safety and durability of the authors’ repair technique using a novel combination of 3 synthetic materials.

Methods. The authors performed a retrospective case review of patients treated for CSF leaks between January 2009 and September 2011. Eight patients were found to have undergone middle fossa craniotomies for CSF leaks. Inclusion criteria for the study included age greater than 18 years, neuroimaging-documented temporal bone defect, and symptoms consistent with CSF leaks or gross CSF otorrhea. Seven patients, 3 men and 4 women, met the inclusion criteria, and their charts were reviewed. Hydroxyapatite cement, collagen-based dural substitute matrix, and polyethylene glycol hydrogel sealant were used in all patients for the repair.

Results. In all patients the MFCSF leaks were successfully repaired. Initial presenting symptoms included CSF otorrhea in 4 patients (57.1%), hearing loss in 3 (42.9%), and CSF rhinorrhea in 1 (14.3%). The mean follow-up duration was 12 months (range 5–33 months). In 1 patient an epidural hematoma developed at the operative site on postoperative Day 2, and in another patient a superficial wound dehiscence occurred on postoperative Day 48. During the follow-up period, the authors found no evidence of wound infections, neurovascular damage, or CSF leakage requiring reoperation.

Conclusions. The middle fossa approach involving a combination of hydroxyapatite cement, collagen-based dural substitute matrix, and polyethylene glycol hydrogel sealant is a safe, effective method for repairing MFCSF leaks. The combination of synthetic materials provides an alternative to existing materials for skull base surgeons.

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Clinical Characteristics and Surgical Outcomes of Patients Presenting With Meningiomas Arising Predominantly From the Floor of the Middle Fossa

Neurosurgery 67:80-86, 2010. DOI: 10.1227/01.NEU.0000370938.46353.77

Little is known regarding meningiomas that primarily arise from the floor of the middle fossa as opposed to the sphenoid wing, the cavernous sinus, the anterior petrous ridge, or the lateral convexity dura.

OBJECTIVE: Given the relative paucity of literature addressing this disease entity, we review the University of California at San Francisco (UCSF) experience with these tumors.

METHODS: Between 1991 and 2006, 1228 patients were seen by neurosurgeons at UCSF for meningiomas of which 17 (1.1%) patients met our criteria for a “middle fossa floor” meningioma, of which 15 underwent first-time surgery and were included in this series. The most common presenting symptoms were headache (9 patients), seizures (6 patients), trigeminal nerve dysfunction (5 patients), hearing loss (5 patients), gait disturbance (5 patients), and cognitive decline (3 patients). All patients underwent surgical resection via frontotemporal craniotomy, with or without orbitozygomatic osteotomy.

RESULTS:We were able to achieve a Simpson grade 1 or 2 resection in 10 of 15 patients (67%). The operative morbidity was clustered in 5 patients, as 10 of 15 patients (67%) experienced no operative morbidity. There were 4 known clinical recurrences in this group at 5 years median follow-up. All patients had either higher grade tumors, or received a Simpson grade 3 or higher resection.

CONCLUSION:We present the clinical characteristics and surgical outcome of a series of patients presenting with meningiomas primarily arising from the concave floor of the middle cranial fossa. Given the relatively uncommon nature of these lesions, more investigation into the clinical behavior of this entity is warranted.

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